Final answer:
An outer join operator is used in computer programming to combine two tables based on a common column, including rows with no matching values. It helps include non-matching rows when combining tables.
Step-by-step explanation:
An outer join operator in computer programming is used to combine two tables based on a common column, including the rows that have no matching values. It is represented by the symbol (-).
For example, let's say we have two tables - Table A and Table B. With an outer join operator, if there is a row in Table A that does not have a matching value in Table B, that row will still be included in the result set. The same applies for rows in Table B that do not have a matching value in Table A.
So, the outer join operator (-) helps us to include non-matching rows when combining tables.